Mycobacterium gordonae Infection Workup

Updated: Sep 08, 2017
  • Author: Klaus-Dieter Lessnau, MD, FCCP; Chief Editor: Mark R Wallace, MD, FACP, FIDSA  more...
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Workup

Approach Considerations

At least three positive culture results or one positive AFB stain result with two positive culture results are required to consider a diagnosis of true M gordonae disease. One positive culture result from a sterile site is probably not enough to start treatment. All cases of possible M gordonae disease should be published in a medical journal.

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Laboratory Studies

See the list below:

  • Documentation of M gordonae disease
  • Microbiologic characteristics, as follows:
    • Smear-positive specimens for acid-fast bacilli
    • Isolation of organism in large numbers, quantified as growth per culture in colony-forming units (ie, >100)
    • Repeated isolation of M gordonae (ie, more than twice)
    • Detection of specific biochemical characteristics (to prove identity)
    • Consideration of confirmation from a reference laboratory
  • Isolation of M gordonae from a sterile source
  • Positive result from tissue culture
  • Histopathologic changes characteristic of M gordonae infection
  • Repeat mycobacterial cultures of sputum, blood, bone marrow, and urine (if disease is suspected)
  • Blood cultures to determine presence of mycobacterial organisms
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Imaging Studies

Obtain a chest radiograph in patients with respiratory symptoms.

Use CT scanning of the lungs, abdomen, or both to evaluate for possible dissemination.

Consider performing abdominal ultrasonography.

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Other Tests

The "3-2-1" rule is useful for a more accurate determination of disease as opposed to contamination or colonization without pathogenicity. To prove disease, one would want to see at least 3 cultures with M gordonae, 2 cultures with one positive acid-fast bacilli smear, or one culture from a sterile source such as blood, bone marrow, or pleural fluid.

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Procedures

Fiberoptic bronchoscopy helps evaluate for infiltrates.

Consider obtaining biopsy specimens (eg, from bone marrow) to help diagnose possible dissemination.

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Histologic Findings

Acid-fast stains are positive for M gordonae, and/or granulomas are present.

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